Al(CON₂H₄)₆Cl₃ was firstly synthesized as a precursor with urea and AlCl₃·6H₂O as a nitrogen source and an aluminum source, respectively, and then the precursor was calcined at 1 000 ℃ to prepare spherical h-AlN nanoparticles. The effects of atmosphere pressure and sintering time on the morphology and the nucleation-growth mechanism of AlN were investigated. The results show that spherical AlN particles with the sizes of 320-460 nm are formed by equiaxed fine grains of smaller than 10 nm and amorphous phase under N₂ pressure of 0.1-0.2 MPa. As the N₂ pressure increases to 0.5 MPa, the diameter of spherical AlN increases to 650 nm, and rod-shaped AlN crystals appear in the aggregates. The size and number of rod crystals increase as the sintering time increases. AlN nanoparticles are formed by the reaction of AlCl₃ and NH₃ due to the decomposition of the precursor. The gas phase saturation in the crucible increases as N₂ pressure increases, promoting the nucleation and growth of AlN, reducing the amorphous phase content, and enhancing the crystallinity of AlN.

Copper-iron matrix composites containing mullite were prepared by powder metallurgy. By adding 0-25% (volume fraction) industrial mullite and high purity mullite respectively, the effects of mullite contents on the mechanical properties and tribological performances of the composites were compared. Furthermore, the influences of graphite content and mullite particle size on the friction performance of the composite were studied as well. With the increase of mullite content, the relative density and bending strength of the composites decreased, although the hardness increased. The coefficient of friction (COF) rose to the highest when mullite content was 15% and the wear rate showed smallest when mullite content was 5%. Compared with high-purity mullite, industrial mullite with wide particle size distribution and various particle shapes had a negative impact on the bending strength and wear rate of the composites. With 15% (volume fraction) graphite addition, the friction coefficient of the composite containing 15% industrial mullite was 0.3-0.4, with a lower wear rate. The industrial mullite with large particle size after sieving selection were beneficial to increase the friction coefficient. However, the industrial mullite with small particle size after ball milling had little effect on increasing the friction, and the wear rate was higher.

Si₃N₄ ceramics were prepared by an oscillating pressure sintering technique when Al₂O₃, Y₂O₃ and TiC additives were introduced into Si₃N₄ powders. The microstructure, grain size and mechanical properties of silicon nitride ceramics at different temperatures (i.e., 1 700, 1 725, 1 750 and 1 775 ℃) were analyzed. The effect of TiC additive on the particle densification and interface bonding of the ceramics were discussed. The results show that Si₃N₄ ceramics can be fully densified at 1 725 ℃ in the oscillating pressure sintering process, thus obtaining a high bending strength of (1 421±59) MPa and the Vickers hardness of (16.1±0.3) GPa, respectively. The aspect ratio of the sample also firstly increases and then decreases with the increase of temperature, and the maximum grain aspect ratio reaches at 1 725 ℃. The aspect ratio decreases and the grains become coarser when the temperature further increases to 1 775 ℃. The flexural strength and the Vickers hardness of silicon nitride decrease with the decrease of length-diameter ratio when the temperature higher than1 725 ℃.

Magnesium alloy has good potential application in bone tissue repair, but it is extremely susceptible to corrosion in the human physiological environment and loses its original mechanical properties, causing the implant material to fail during service. In order to improve its corrosion resistance and ability to rapidly induce apatite in vitro, a one-step hydrothermal method was used to prepare a micro-nano structured hydroxyapatite coating on magnesium alloys. The polarization resistance of the sample reached 138.680 kΩ·cm², indicating that the sample has excellent electrochemical performance. The degradation performance of the sample was tested in simulated body fluids. During the 30 d immersion time, the pH value of the simulated body fluids were maintained in the range of 7.10-7.60, and the corrosion rate was lower than 0.400 mm/y. And when immersed for 3 d, hydroxyapatite mineralization were formed on the coating surface, indicating that the micro-nano structural coating can quickly induce the formation of Ca-P products and has good mineralization ability.

SiC/Al composites were prepared by a pressureless infiltration process using SiC powder and aluminum alloy (3%Mg (in mass fraction), 5%Mg, 7%Mg, and 10%Mg) as main raw materials. The phase composition, microstructure, mechanical properties and thermal properties of SiC/Al composites were characterized. The effect of Mg content in aluminum alloy on the phase composition, microstructure, mechanical properties and thermal properties of SiC/Al composites was investigated. The results show that Mg can improve the impregnation properties of aluminum alloys and promote the occurrence of interfacial reaction in SiC/Al composites. The main crystalline phases of the prepared SiC/Al composites are both SiC and Al. The presence of Si, Mg₂Si and MgAl₂O₄ phases is also detected. After comparison, the sample with 5% Mg performs the better properties. The optimum performance of the sample prepared with 5%Mg (i.e., flexural strength of (366.36±14.37) MPa, fracture toughness of (9.2±0.27) MPa·m^1/2 and thermal conductivity of 178.81 W/(m·K) can be obtained when the porosity is 0.13% and the bulk density is 2.94 g/cm³.

The porous mullite-based ceramics were prepared by a particle-stabilized foam method and a subsequent freeze-drying process with α-Al₂O₃ and SiO₂ as raw materials, propyl gallate (PG) as a surface modifier and gelatin as a binder. The effect of aluminum to silicon (Al/Si) molar ratio on the composition, microstructure and properties of the prepared materials was investigated. The results show that the foam stability after foaming at different proportions is >95%. The sintered material is composed of mullite as a main phase and corundum as a second phase, and the mullite phase content decreases from 93.11% (in mass fraction) to 85.11% with increasing the Al/Si molar ratio from 2.0∶1.0 to 3.0∶1.0. The total porosity and bulk density are 85.51%-86.51% and 0.44-0.48 g/cm³, respectively. The open porosity is 84.34%-84.82%. The compressive strength firstly increases and then decreases (i.e., 2.25-2.86 MPa). The vacuum thermal conductivity increases from 0.15 W/(m·K) to 0.22 W/(m·K). It is indicated that the method could be promising to prepare porous mullite-based ceramics with a high porosity, a high strength and a low thermal conductivity.

The sintered Al₂O₃ blocks with some properties similar to Al₂O₃ inclusions in ingot were investigated, and the fracture behavior of Al₂O₃ during deformation was analyzed by high-temperature compression experiments in a special hot compression device. Based on the analysis of fracture characteristics of crushed samples, a prediction model of high-temperature crushing strength of Al₂O₃ was proposed based on the hyperbolic sinusoidal Arrhenius equation, the region map of crushing mode of Al₂O₃ characterized by Z parameter was constructed, and the crushing mechanism of Al₂O₃ at different deformation parameters was revealed. The results show that the hot compression process of Al₂O₃ has a typical brittle fracture, i.e., its crushing strength is positively correlated to the strain rate and it is negatively correlated to the deformation temperature, and it is more sensitive to the deformation temperature. The crushing mode of Al₂O₃ inclusions gradually changes from transgranular fracture to intergranular fracture when the Z parameter decreases.

The failure mechanisms of SiC, B₄C ceramic and the laminated SiC/BN composite armor under ballistic impacts of 5.8 mm steel bullet at 920 m/s were investigated by the finite element analysis and ballistic experiments. The results show that the fracture toughness of laminated SiC/BN ceramic with weak interfaces is 7.6 MPa·m^1/2. The shear fractures of substrate and interlayer appear on the ballistic impact surface, and the delamination and folding fractures occur at the back. The more transgranular fractures occur when the interlayers increase, compared to the intergranular fractures. The shallower impact craters are generated when the thickness of the SiC substrate layers decreases along the impact direction. SiC/BN laminated ceramic has a better ballistic performance when the mass fraction of BN interlayer is 6.9%, and SiC and B₄C block ceramics exhibit a better ballistic performance under multiple bullet impact condition.

A series of nonstoichiometric (NaBi)_0.47Ba_0.06TiO₃ (NBT-6BT) ceramics were prepared by the conventional solid-state method. The impact of A-site nonstoichiometry on the structural and electrical properties of the prepared ceramics was investigated. The room temperature diffraction patterns and Raman spectra revealed the coexistence of the Cc and P4bm phases for all samples. The experimental results in the present work showed that a deficiency in the Bi³⁺ and Na⁺ contents could lead to a transformation from the Cc to P4bm phase in addition to a variation in the piezoelectric coefficient d₃₃ with the Cc phase fraction. Favorable thermostability for the piezoelectric properties of the ceramics was observed by testing the depolarization temperature (T_d). Among them, the d₃₃ of the N_0.32B_0.32T-6BT ceramics still had a value of 23 pC/N at 160 ℃. These results showed that a deficiency in the Na⁺ and Bi³⁺ contents can significantly enhance T_d and extend the temperature region for the application of NBT-6BT ceramics.

Lead-free single-phase perovskite BaTiO₃-Bi(Al_0.5Sc_0.5)O₃ ceramics as novel high performance BaTiO_3-based energy storage ceramics were synthesized by a solid-state reaction method. Effect of BAS content on the structure, dielectric properties, energy storage of (1-x) BT-xBAS ceramics was investigated. The (1-x)BT-xBAS solid solution transforms from tetragonal (x≤0.05) to cubic (x≥0.1), but is still based on the tetragonal. The T_m moves toward a low temperature range, and the dielectric peak broadens with the BAS content increases, exhibiting a dispersive dielectric behavior with respect to frequency. The long-range ferroelectric order of ceramics is destroyed by BAS. Also, the phase transition of BT-xBAS ceramics is from a typical ferroelectric phase to a relaxor phase. The phenomena both indicate that the BT-BAS ceramics could have the excellent characteristics of relaxor ferroelectrics. The 0.85BT-0.15BAS ceramics show a good temperature stability, and the diffusion coefficient γ is 1.97. There are an energy storage density of 0.684 J·cm^-3 and an energy efficiency of 95% in an electric field of about 105 kV/cm.

An ITO green body was prepared via molding-assisted cold isostatic pressing with gasified In₂O₃ and SnO₂ powder (n(In₂O₃)/n(SnO₂)=9∶1). The ITO targets with different Sn contents were sintered in oxygen atmosphere at 1 550 ℃. The target samples were ground and then corrosion products were extracted after sieving and being corroded. The microstructure, phase composition, density and resistivity of the target surface and corrosion products at different Sn contents were analyzed. The results show that the corrosion product is the second phase-In₄Sn₃O₁₂ of the ITO target. The grain size of the ITO target decreases with the increase of SnO₂ content, and the second phase of the grain boundary gradually increases and stabilizes at below 3 μm. The size of small particles in the ITO target increases with the increase of SnO₂ content and is stable below 100 nm. The second phase of the target has a trace amount of oxygen loss at the loss rate of 1.1%. The actual and theoretical densities of the target increase with the increase of SnO₂ content. The measured density increases from 7.110 to 7.145 g/cm³ and the resistivity of the target increases from 1.3×10^-4 to 1.9×10^-4 Ω·cm with the increase of SnO₂ content.

Ceramizable silicone rubber was prepared via sintering at 1 000 ℃ with MVQ as a matrix, wollastonite as a ceramic filler, glass powder as a flux and fumed silica as a reinforcing agent. The effect of glass powder content on the electrical and mechanical properties of ceramizable silicone rubber was investigated, and the samples were characterized X-ray diffraction, thermogravimetric analysis and bending strength measurement. The results show that glass powder can weaken the electrical and mechanical properties of silicone rubber slightly, reduce the decomposition temperature of silicone rubber, and improve the bending strength of the ceramics. The analysis of the ceramics microstructure indicates that the density of the ceramics increases with increasing the glass powder content. Based on the results by X-ray diffraction, wollastonite disappears after ceramization, which reacts with glass powder to form a new crystal. The bending strength is 61.1 MPa when the glass powder content is 12 g.

To ensure the color, near-infrared (NIR) reflectance as well as the thermal and chemical stabilities of zinc selenosulfide (ZnS_xSe_1-x) pigment, co-precipitated ZnS_xSe_1-x precursors were in-situ encapsulated with mechanically activated zircon (ZrSiO₄) precursors by homogeneous mixing and subsequent sintering at a lower temperature. The structure, morphology, thermal stability and chromatic property of ZnS_xSe_1-x@ZrSiO₄ encapsulated pigment were investigated, and the thermal insulation property of ceramic tiles coated with ZnS_xSe_1-x@ZrSiO₄ pigment was evaluated. The results show that mechanical activation can improve the activity and homogeneity of ZrSiO₄ precursor, thus reducing the activation energy of ZrSiO₄ crystallization and facilitating the formation of ZrSiO₄ at a lower temperature. The crystal formation of activated ZrSiO₄ precursors occurs simultaneously with the synthesis of ZnS_xSe_1-x pigment, and ZrSiO₄ grains are formed in-situ on the pigment particle surfaces. ZrSiO₄ grains gradually grow up and densely encapsulate ZnS_xSe_1-x pigment during subsequent sintering at a lower temperature (i.e., 700 ℃). The ZnS_xSe_1-x@ZrSiO₄ encapsulated pigment possesses the superior chromatic property, thermal and chemical stabilities as well. Compared to white ceramic tiles, ceramic tiles coated with ZnS_xSe_1-x@ZrSiO₄ pigment absorb less NIR radiation (energy), thus exhibiting a lower surface temperature and a good thermal insulation property.

Yttria-stabilized zirconia (YSZ) supports with directional straight open pores were prepared by an alginate self-organization method. Ni nano-particles were impregnated into the porous supports to obtain the anodes for solid oxide fuel cells. The results show that the pore size of YSZ supports decreases with the increase of solid content and CaCl₂ solution concentration. The open circuit voltage of Ni-YSZ/YSZ/LSM-SDC cell is above 1 V at 650 ℃ and the maximum power density at 800 ℃ is 225 mW/cm² by using hydrogen as fuel and air as oxidant. It is expected that the output performance of the cell could be further improved by adjusting the porosity of the anodes and the thickness of electrolyte, and the application of the ceramics with straight open pores straight ceramics in solid oxide fuel cell could be realized.

The formation process of amorphous photonic crystal structure in glaze melt and its visible light enhanced-reflection mechanism were analyzed. In a multi-component glaze system, an appropriate amorphous photonic crystal structure was obtained via controlling calcite content. The results show that introducing a proper amount of calcite can promote the effective phase separation of glaze melt, leading to a Si-rich phase and a cation-rich phase. The special core-shell particle can be formed due to the enrichment of the strong-polar cation such as Ti, Zn, Ca, and Mg in the interface. An opal amorphous photonic crystal structure appears for the short-range ordered arrangement in glaze layer. However, an inverse opal amorphous photonic crystal structure is formed at the interface between glaze and body. The visible light reflectivity of glaze surface is improved due to the effect of the two structures.

Luminescent amorphous silicon oxycarbide (α-SiC_xO_y) films with different C concentrations were prepared via a high-frequency plasma enhanced chemical vapor deposition system. The fabricated α-SiC_xO_y films have an intense white photoluminescence (PL). It is indicated that the increase of C concentrations in the films from 23% to 34% increases the PL intensity by more than 30 times. The PL peak positions are independent of the excitation wavelengths. Based on the Raman spectra and Si 2p XPS spectra, the films are amorphous carbon-rich SiC_xO_y phase. According to the PL results and the analysis of the bonding configuration of the films, the enhanced PL is related to the reconstruction of C-related chemical bonds in the films.

Pure LaAlO₃ and Ca²⁺-Cr³⁺ co-doped LaAlO₃ ceramic materials were prepared via a high-temperature solid-state reaction in air atmosphere. Their near-infrared (NIR) emissivity and thermal conductivity were investigated. The results reveal that 20% Ca²⁺ and 20% Cr³⁺ co-doped LaAlO₃, namely La_0.8Ca_0.2Al_0.8Cr_0.2O₃, has a greater NIR emissivity of 0.92 in the wavelength range of 0.76-2.50 μm, which is 300% greater than that of pure LaAlO₃. The thermal conductivity of LaAlO₃ can be reduced by Ca²⁺-Cr³⁺ co-doping. The minimum thermal conductivities of LaAlO₃ and La_0.8Ca_0.2Al_0.8Cr_0.2O₃ both appear at 1 200 ℃, and the minimum thermal conductivity of La_0.8Ca_0.2Al_0.8Cr_0.2O₃ is 2.602 W·m^-1·K^-1, which is 38% lower than that of pure LaAlO₃.

MgO-doped K_0.5Na_0.5NbO₃-based lead-free piezoelectric single crystals were prepared by a seed-free solid-state crystal growth method. The effect of MgO doping on the growth, microstructure and piezoelectric ferroelectric properties of K_0.5Na_0.5NbO₃-based crystals was investigated by X-ray diffractometer, scanning electron microscope and piezoelectric ferroelectric tester. The results show that MgO-doped K_0.5Na_0.5NbO₃-based single crystals can be prepared by a seed-free solid-state crystal growth method. The MgO doping does not change the crystal structure of K_0.5Na_0.5NbO₃-based single crystal, and MgO dissolves into the lattice of potassium sodium niobate to form a uniform solid solution. An appropriate MgO doping content is beneficial to improving the piezoelectric and ferroelectric properties of K_0.5Na_0.5NbO₃-based single crystals and decreasing its dielectric loss. When the doping content of MgO is 0.6%, the piezoelectric constant of K_0.5Na_0.5NbO₃-based single crystal (d₃₃) is 203 pC/N, the dielectric loss (tanδ) is 0.028, the dielectric constant (ε) is 221, the coercive electric field (Ec) is 7 kV/cm, and the residual polarization intensity (P_r) is 36.5 μC/cm².

A complex [Fe(2,2'-bpy)₂Ni(CN)₄]_n (1) was synthesized with K₃[Fe(CN)₆] as a source of cyanide anions and Fe²⁺ cations, 2,2'-bipyridine (2,2'-bpy) and Ni(Ac)₂·4H₂O under hydrothermal condition. Based on the X-ray crystallographic studies, two cations Fe²⁺ and Ni²⁺ are alternately bridged by some cyanide ligands to form a 1D zigzag chain with 2,2'-bpy terminal ligands in complex 1. The thermogravimetric analysis shows that a bimetallic complex [Fe(2,2'-bpy)₂Ni(CN)₄]_n has a good thermal stability. The magnetic measurement reveals an intense antiferromagnetic interaction between iron and nickel ions in complex 1.

CVDZnS samples were prepared by a chemical vapor deposition method at different deposition temperatures (i.e., (650±10), (670±10), (700±10) ℃ and pressures (i.e., (5 000±200), (7 000±200), (9 000±200) Pa as well as a H₂S flowrate of (2±1) L/min and an argon flowrate of (35±2) L/min. The CVDZnS samples were analyzed by X-ray diffraction, metallographic microscopy and Fourier transform infrared spectroscopy, microscopic grain morphology and infrared transmittance measurement at 2-15 μm. Based on the XRD characterization, CVDZnS mainly exists in the form of cubic phase with a small amount of hexagonal phase and the preferential orientation of deposition growth is s(111). The metallographic analysis indicates that the average grain size increases with the increase of temperature when the deposition pressure is (5 000±200) and (7 000±200) Pa, and the maximum average longitudinal grain size is 15.5 μm. The bending strength test data show that the ratio of average longitudinal grain size to average transverse grain size is closer to "1", which is more advantageous to increase the bending strength of materials. In addition, the CVDZnS prepared at (670±10) ℃ and (7 000±200) Pa can effectively improve the average transmittance of 2-5 and 7-10 μm (i.e., 72.15%) and reduce the absorption at 6.0 μm.

A mullite-cordierite saggar was prepared with mullite, cordierite, α-Al₂O₃, talc and Kaolin clay, and the room-temperature mechanical properties, thermal shock resistance and erosion mechanism of saggar in sintering process of LiCoO₂ were investigated. The results show that the better mechanical properties and thermal shock resistance of the saggar can be obtained when sintering at 1 350 ℃. The bending strength of sample is 11.18 MPa and its residual strength retention rate after three cycles of thermal shock is 44.8%. In the process of sintering LiCoO₂, a mullite-cordierite saggar is attacked by Li₂O, producing LiAlSiO₄, Li₄SiO₄ and LiAlO₂. Li₂O diffuses into the sagger along the pores, and the structure of the permeation layer is denser after the reaction, which can hinder Li₂O from further attacking the sagger, thus giving a good erosion resistance of mullite-cordierite sagger.